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Emergency Preparedness and Response: School Dismissals to Reduce Transmission of Pandemic Influenza


What the CPSTF Found

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review of 67 papers. The systematic review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to emergency preparedness and response.


During an influenza pandemic, the coordinated closure of schools could be an important community-wide public health action. If implemented efficiently and maintained for an appropriate duration, school dismissals could reduce or delay transmission of infection; reduce the burden of illness on communities, health systems, and providers; provide time to implement additional public health actions (such as distribution of an effective vaccine); and reduce morbidity and mortality caused by the pandemic. The closure of educational facilities for the required duration, however, will involve costs to households and communities, due to social disruption and related economic effects. Against these costs, benefits from reduced morbidity and mortality (and related social and economic effects) could vary, depending on how easily the infection is spread, the severity of illness, and effectiveness of the overall public health response.

In conducting this review, the CPSTF considered the available evidence regarding benefits and costs of coordinated school closures for an extended duration (weeks to months). The CPSTF finding is an assessment of the overall value of coordinated school closures to the community during an influenza pandemic. Many dismissal decisions will be made locally, by school and public health officials who incorporate local considerations and information. Although the decision to close individual schools (especially schools with students at elevated risk for complications of influenza) during high or increasing rates of illness, absenteeism, or public concern remains a local option, such actions alone are unlikely to affect community-wide transmission of pandemic influenza.

Summary of Results

  • Five studies used historical sources to reconstruct community mitigation actions taken by major cities in the United States and Australia during the 1918 pandemic.
    • Cities that quickly closed schools in combination with other interventions experienced lower regional death rates (by as much as 30-40%), although relaxation of these policies was frequently associated with secondary peaks in pandemic-related mortality.
  • Thirty-one studies examined pandemic or seasonal influenza transmission in relationship to school operations. Most described limited evaluation of short term reactive school closures in response the 2009 pandemic H1N1 or outbreaks of seasonal influenza.
    • Several of the studies showed reductions in school or community illness, but few looked at comparisons between schools that were closed and schools that remained open
  • Thirty-one published papers described computer-based models of community actions and outcomes during a simulated influenza pandemic.
    • Across a range of simulated pandemic scenarios, pre-emptive, extended duration school dismissals reduced transmission, delayed and blunted peak rates of illness, and reduced hospitalizations and deaths.
    • The combination of school dismissals with additional interventions such as anti-viral distribution programs or additional changes in social distancing, demonstrated an even larger impact on pandemic influenza transmission, illnesses, and deaths.

Summary of Economic Evidence

  • The economic evidence included 20 studies:
    • Eleven studies used actual school dismissals and focused on household costs during short term closures.
    • Nine modeling studies examined societal economic costs and benefits from extended school dismissals across a range of influenza pandemic scenarios.
  • Simulation models identified substantial costs to school districts, students, parents, and employers with extended school closures irrespective of the impact of the closures on pandemic influenza transmission and illness.
    • In simulations of pandemics with low severity of illness, the costs of extended duration closures exceeded the economic benefits accrued from reduced transmission and illness in the community.
    • In scenarios where transmissibility, severity of illness, and case fatality were high, school dismissals averted substantial morbidity and mortality leading to reduced health care costs, reduced productivity loses associated with work absences, and greater overall quality adjusted life years for the population.
  • Two economic simulations of school dismissals combined with additional interventions in response to severe pandemics reported net cost per quality adjusted life year saved within a conservative threshold of $50,000.


  • The Task Force notes several limitations in the applicability of the available evidence to school and public health decisions.
    • Unique characteristics of the next pandemic may influence the effectiveness of school dismissals or other public health actions.
    • Public health actions and effects during the 1918 pandemic may not apply now.
    • Findings from community simulation models may not accurately represent real world scenarios.
    • Costs and benefits of short term school dismissals may not be useful predictors of costs and benefits of extended duration closures.
    • Findings from studies of seasonal influenza may not apply to pandemic influenza.
    • Evidence on influenza transmission associated with school openings may not apply to school closure decisions.

Evidence Gaps

CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)

More research is needed to inform future assessments of school dismissals as a pandemic response option.

  • Studies documenting the transmission, clinical severity, mitigation actions, and economics of the 2009 H1N1 pandemic should provide information for use as comparison experiences in modeling simulations and economic assessments.
  • Future simulations of influenza pandemics should explore the threshold margins of effectiveness of school dismissals (points at which the benefits to costs trade-offs change) based on differences in pandemic impact, school dismissal timing and duration, and the presence or absence of additional community mitigation actions.
  • Studies should explore the potential value of school dismissals of shorter duration (1-3 weeks) implemented with the primary intent of reducing the peak burden on health care resources.
  • Community simulation models should include organized child care facilities as an additional setting associated with influenza transmission. Simulations should model the timing and completeness of child care closures separately from the timing of school dismissal decisions.

Study Characteristics

  • Studies included in the effectiveness review were as follows:
    • Five retrospective analyses of public health actions taken by different cities during the 1918 pandemic
    • Thirty-one studies of actual school actions (dismissals, holidays, or openings) in the setting of pandemic influenza or seasonal influenza outbreaks
    • Thirty-one papers based on results from community simulation models.
  • Thirteen the effectiveness studies or models provided estimates on economic effects of school dismissal interventions, either alone or as part of a combined pandemic response.